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A simulation is a conversation between a Coval-driven user and your voice or chat agent. Instead of testing your agent by hand, Coval plays the role of a realistic user, talks to your agent end to end, and then evaluates how the conversation went against criteria you define. You run simulations to catch regressions before they reach production, measure how your agent performs across many different users and scenarios, and understand exactly where and why a conversation goes wrong. Coval supports two kinds of simulations:
  • Text-based — for chat agents using text inputs and outputs.
  • Voice-based — for voice agents with audio inputs and outputs.

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What you need to set up a simulation

A simulation brings together four building blocks. Each answers a different question about the test, and each lives in its own section of Coval so you can reuse it across many simulations.

Agent

Who is being tested. A reusable connection to your voice or chat agent. Without an agent, there’s nothing to talk to — this is how Coval reaches your system.

Persona

Who is doing the talking. The simulated user — their voice, accent, and behavior. Personas let you test how your agent holds up against the range of real people it will actually meet.

Test Set

What the conversation is about. A collection of test cases (scenarios, goals, scripts) that tell the simulated user what to do. This defines the situations you want to cover.

Metrics

How you measure success. The pass/fail criteria applied to each conversation — from latency and sentiment to custom LLM-judged questions. Metrics turn a transcript into an answer about whether your agent did its job.
Once you have these, you don’t have to wire them together by hand every time. A Template saves a combination of agent, persona, test set, and metrics so you can launch the same evaluation consistently — or schedule it to run on a recurring basis.

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Launching a simulation

When you launch an evaluation, Coval starts the simulation and then evaluates the result. A single launch is called a run, and a run can contain many simulations at once — for example, one per test case in your test set. Head to the Simulate page and follow these steps: The Simulate page — configure the agent, persona, test set, and metrics for a run The Simulate page — configure the agent, persona, test set, and metrics for a run
1

Open the Simulate page

Click Simulate in the sidebar to open the page where you’ll configure your run.
2

Pick a template, or configure manually

Start from a saved template for a one-click launch, or set it up yourself:
  • Select an agent to test
  • Select a persona
  • Choose a test set
  • Set your simulation parameters
  • Choose the metrics to track
  • (Optional) Add tags to label this run
3

Launch

Click Launch — Coval runs the simulations and evaluates them against your metrics.
Once launched, every run appears on the Runs page — the list of all your evaluations, where you can read the results and dig into individual conversations to see exactly where things went right or wrong.

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Re-running a simulation

If a single simulation looks off, select it in the run’s results table and click Resimulate to run it again in place against your latest configuration. This overwrites the previous result, so launch a new run instead if you want to keep the old one for comparison.

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Time limits

Each simulation runs up to 10 minutes by default and 15 minutes at most. It ends when the conversation wraps up naturally, the objective is met, or the timeout is reached — whichever comes first. If you need longer conversations, contact support@coval.dev.

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Next steps

Connect your agent

Set up the connection to your voice or chat agent.

Launch your first run

Put the pieces together and run your first evaluation.